We're currently trying to figure out what a pipe coming out of the floor of our 1905 house.

We are located in Ottawa, Ontario, Canada.

The pipe is about an inch in diameter and capped. The cap has a 'G' on it. It looks very old, as there is significant corrosion on it. I can't get it open without heating it, and I haven't yet tried that.

I thought it might be the pipe leading to an undeground oil resevoir, but I don't think this is the case for two reasons. First, it is very rare that oil resevoirs would be underground in such an old house. Second, I already can see where the oil line ran from outside the house to the inside.

If anyone had any guesses on what this might be, or just a general direction, I'd be very grateful.

The G is not significant. It is only the plug manufacturers mark. It is not indicative of GAS if that is what you where thinking.

Do you know of this house ever had well water? The pipe could be from an old well. It could also less likely be a old gas line into the house. 1" is a pretty standard size for both water and gas. Gas doesn't normally come up through the floor. They don't usually bury it that deep.

Before you actually cut it I would remove the plug. If it was for oil you would probably smell it. If it was from a well there is a slight possiblilty that water might come out. Maybe even dip a stick into it and see what's there.
You can always put the cap back on. Once you cut you are done and won't be able to cap it if you find something strange.

Before you actually cut it I would remove the plug. If it was for oil you would probably smell it. If it was from a well there is a slight possiblilty that water might come out. Maybe even dip a stick into it and see what's there.
You can always put the cap back on. Once you cut you are done and won't be able to cap it if you find something strange.